A clutch control device of the kind defined above is described in U.S. Pat. No. 4,529,075. In that arrangement, the manoeuvring member is provided with a transverse radial portion, while the retaining shroud is rigid and includes an annular lateral wall defining a shoulder on which the working element bears, with the said resilient member being axially confined together with a portion of the working element, between the said radial portion and the said shoulder. The resilient member bears on the working element and on the radial portion, in such a way that the working element is resiliently trapped between the radial portion and the shoulder. The assembly means, mentioned above, allow the working element to be assembled with the manoeuvring member, and comprise a plurality of lugs or tabs, resiliently deformable radially and forming part of the manoeuvring member, these tabs being hooked on to notches formed in the retaining shroud, and being maintained in engagement with these notches by the action of the said resilient member.
In service, and especially having regard to the effect of vibrations of the vehicle and shock forces, the lugs or tabs, being resilient, can sometimes escape from the notches formed in the retaining shroud, thus causing the assembly to disintegrate.
In addition, in certain cases it is necessary to make the lugs or tabs thinner, so that they are sufficiently flexible to enable them to be snapped into place during assembly. This however complicates the manufacture of the manoeuvring member. Furthermore, such an arrangement is not universally applicable, since it is somewhat difficult to apply in practice when the manoeuvring member has a transverse radial portion having no lateral wall or the like at its outer periphery. Finally, certain of the arrangements described in the above mentioned United States patent specification cause weakening of the retaining shroud.